Spark-plug-testing device



' Dec. 18, 1 928.

R. H. MYERS SPARK PLUG TESTING DEVICE Original Filed April l6. 1926 m m T (Q,

if 1-3,, X3 5 gwmmto'o RoyHMyers Patented Dec. 18, i928.

UNITED STATES I 1,695,557 PATENT OFFICE.

ROY H. MYE RS, OF HAGERSTOWN, MARYLAND, ASSIGNOR TO WILLIAM H. STRAUSS,

- F WAYNESBORO, PENNSYLVANIA.

SPARK-PLUG-TESTING DEVICE.

Application filed April 16, 1926, Serial No. 102,529. Renewed March 12,- 1928.

My said invention relates to a spark plug tester and it is an object of the invention to provide means for insuring the safety of the user against possible damage to his eyes by reason of explosion of gasoline on the term1- nals of the plug being tested, 'or gasoline vapor in the compartment in which the terminals are located at the time of testing. Referring to the accompanying drawings which are made a part hereof and on which similar reference characters indicate similar parts, I

Figure 1 is a plan of my device, Figure 2, a vertical longitudinal section of the same, and

Figure 3, a wiring diagram. In the drawings reference character 10 indicates the base on which the other parts of my device are supported, said parts ineluding side walls 11 and a cover 12 for the main compartment in which are located a transformer 13 and a coil 14', -A gage 15 is here shown 'as located in an openin in the cover 12 but may, of course, be ot erwise positioned provided only that the face of the ga e is in plain view. o

it the forward end of the main compartment a mirror 16 is supported in inclined position in such a way asto. render visible to the user theinterior of a small compartment 17. This compartment is formed inthe front of the device in a casing'18 of any suitable material adapted to have formed therein threaded Openings for supporting spark plugs or sealmg plu s such as indicated at 19, 20 and 21. T e casing 18 is spaced from the frontwall of the main compartment by a sheet 22 of cork or any other suitable packing, said packing surrounding the rear opening in the front com artment and the smaller openings 23 in t e front wall of the rear compartment so as to render the compartment 17 air-tight. 'A sheet of glass 24 is located in any suitable manner between the two compartments so as to provide a transparent wall covering the openings 23. Another sheet of glass 25 is'situated in an o ening in the cover 12 directly above the mirror. Bolts 26, or other suitable means, are provided for securing the casing 18 to the front wall of the rear compartment whereby the packing may be compressed to insure a tight fit.

An air valve is mounted in the wall of .the

casing 18 so as to register with a passage 27 in said wall this valve being: provided with a nipple 28 for connection to any suitable source of air under pressure. A suitable handle 29 is provided for opening and closing the passage through the valve. A safety valve 30 provides means whereby excessive pressure in the anterior chamber 17 maybe relieved automatically. A-passage 31 leads through said chamber to the safety valve whereby the operator may take note of the pressure in the chamber, it being understood that the terminals 32 and 33 of the plugs should be surrounded by air under pressure equivalent: to that in an internal combustion engine. The front of the chamber is provided with three openings, as shown, for receiving therespective plugs 19, 20 and 21. The plug 19 has "an ordinary spiral thread; the plug 20 has a tapered base with a pipe thread, and the plug 21 is provided with a metric thread. This arrangement provides means whereby any type of plug in ordinary use may be tested with facility.

The current for use in the device enters 30 by way of a main line comprising conductors 34 and 35 leading to the main coil of the transformer .36. Conductor 35 is provided with a switch in the form of push button 37 eoacting with a terminal 38. '35 The secondary coil 39 of the transfbrmeris connected atone end by a conductor 40 to the vibrating spark coil 14. A high tension conductor 41 leads from the spark coil to the spark plug being tested, said conductor being provide with a spark gap at 42, the purpose of said safety gap being to prevent shocks to the operator when the terminal 43 of the high tension wire is off the plug. Another conductor 44 leads. from the coil to the secondary coil of the transformer, said conductor. being grounded on the casing 18 at 45 whereby the current may pass from the spark coil through the high tension conductor 41, the terminals 43, the plug being tested, the casing 18, andthe portion of the conductor between the ground 45 and the coil 39. V

In the use of my device a plug is positioned in that one of the openings suited for the purpose, the other openings being closed either b a suitable spark plug or by any other p ug which willclose the opening and prevent the escape of .com ressed air. Compressed air is admitted to t e compart- 0 ment 17 until the gage shows sufficiently high pressure to equal the actual working conditions of the spark plug as used in an internal combustion engine. The terminal 43 is positioned on the upper end of the spark plug. The push button may now be operated for the purpose of testing the plug, it-being noted that push button should not be moved until the connection has been made with the spark plug to prevent loading the terminal 43. In apparatus of this character previously used it has been found that the gasoline with which the plugs are cleaned will sometimes explode and cause'trouble.

With a device such as has'heretofore been used, having a transparent wall 24, an explosion will .sometimes blow out the glass 24 with consequent injury to the operator and with special danger of injury to his eyes since the wall is made transparent for pur oses of observation of the lug. In my device such danger is effectual y prevented, first, by reason of the fact that observations are taken looking down on the mirror so that glass blown out of the-apparatus would fly against the mirror instead of directly toward the operator and second, because the 'wall 25 will arrest any glass that might be projected toward the operator on rebound from the mirror. The space between the mirror and the plates 24 and 25 'serves to relieve the pressure in the chamber and further relief ma be had, if desired, by providin the sldes 11 or at the bottom of the space below the plate 25.

' art that various changes ma m It will beobvious to those skilled in the be made in my device without de arting rom the spirit of the invention and t erefore I do not limit I myself to .what is shown in the drawings ing, a pressure chamber in said casing hav- 'mg a: transparent wall portion, said casing and described in the specification but only as indicated in the appended claims.

Having thus full described my said invention, what I clalm as new and desire to secure by Letters Patent, is:

1'. A spark plug tester comprising a cashaving a transparent wall portion disposed at an angle to said transparent wall portion of the pressure chamber, and a mirror disposed m a position to permit the interior of the pressure chamber to be observed forth.

a suita le opening either in one ofv through both transparent wall portions, substantially as set forth.

2. A spark plug tester comprising a cas ing, a pressure chamber in said casing having a transparent yieldingly supported wall portion, said casing having a transparent wall portion disposed at an angle to said trans arent wall portion of the pressure chamber, and a mirror disposed in a position to permit the interior of the ressure chamber to be observed through bot 1 transparent wall portions, substantially as set 3. A spark plug tester, comprising a pressure chamber having a removable transparent wall portion, means for supporting a spark lug with its terminals in front of said wall portion, an inclined mirror spaced from said wall portion, and a transparent wall portion at an angle to said first-mentioned wall portion through which said terminals may be observed from said mirror, substantially as set forth.

' 4. A spark plug tester comprising a pressure chamber having a removable transparent wall portion, a pressure gage conspark plugs in the front wall of said auxiliary cas ng, sight apertures behind said spark plugs, a mirror behind said apertures, a trans arent shield in the main casing over said mirror through which the spark plugs can be viewed in the mirror, and connections from said coil to said spark plugs, substantially as set forth.

. In witness whereof, I' have hereunto set my hand at Washington, District of Columbia, this fifteenth day of April, A. D. nineteen hundred and twenty-six.

ROY H. MYERS.

unit having a main casing con- 

